Monaural informational masking release in children and adults

Abstract

Informational masking refers to an elevation in signal threshold due to stimulus uncertainty, rather than to energetic masking. This study assessed informational masking and utilization of cues to reduce that masking in children aged 5–9 and adults. We used a manipulation introduced by Kidd et al. [J. Acoust. Soc. Am. 95, 3475–3480 (1994)] in which the signal was a train of eight consecutive tone bursts, each at 1 kHz and 60 ms in duration. Maskers were comprised of a pair of synchronous tone-burst trains whose frequencies were selected from the range spanning 0.2–5 kHz, with a protected region 851–1175 Hz. In the reference condition, where informational masking is pronounced, these maskers were eight bursts and had a fixed frequency within each interval, with new frequencies chosen randomly prior to each interval. Two conditions of masking release were tested: random frequency selection for each masker burst and a masker leading fringe of two additional 60-ms bursts. Both children and adults showed a significant informational masking effect, with children showing a larger effect. Both groups also showed significant release from masking, though initial results suggest that this may have been reduced in the youngest children. [Work supported by NIH, RO1 DC00397.]